This invention relates to movement and control of objects.
The current lack of manufacturing techniques for very high volume handling of small objects presents a technology barrier to commercial success in various fields of Microsystems technology (MST) such as microelectromechanical systems (MEMS). A fundamentally new approach to automated massive parallel manipulation of small-sized objects or parts is needed and is provided by this invention.
Mass production of miniature components such as integrated circuits, micro electromechanical systems (MEMS), and the like, requires fundamental innovations in parts handling. Components of such systems are built using microfabrication processes derived from VLSI technology, which allows the manufacture and handling of thousand or millions of components in parallel. The pneumatic active surface device (PASD) disclosed herein uses a new approach to automated object manipulation. Instead of handling a single object directly, for example, with a robot gripper, a pneumatic active surface device can be used to manipulate multiple objects simultaneously. This new automation device permits parallel and distributed, sensing and actuation, and is particularly attractive for handling batch microfabricated objects, whose small dimensions and large numbers don""t allow conventional pick and place operations with robot grippers. Accordingly, there is a particular need for methods and equipment to provide such capability.
This invention provides a pneumatic active surface capable of sensing, locating, and moving, holding, and releasing an object on the surface by selective activation of the blow or suck function of individual tubes or groups of tubes of the surface. Sequential blowing or sucking of a gaseous fluid through the selected tubes creates vibrations and fluid flow patterns which cause the object to move. Sucking on a tube or group of tubes causes the object to be fastened or fixed to that region of the surface. Blowing raises the object or a portion of the object above the surface.
The active surface comprises an array of pneumatic conduits which are individually adapted to carry a gaseous fluid such as air to the surface or draw from the surface. In the case of tubes the tubes which are the conduits are arranged so that the end wall of each tube form a relatively flat surface with air conduits provided by the bores of the tubes. The term xe2x80x9ctubexe2x80x9d or xe2x80x9ctubesxe2x80x9d refer to a slender channel, usually circular, within a body. The surface could be in the form of a flat body such as a wafer of suitable material and thickness having a plurality of passages or conduits from top to bottom drilled or constructed therethrough. The lower surface of the body is connected to the fluid sources and the sensors and valves can be carried within the channel which passes through the body. The tubes or conduits may be distributed over a relatively wide surface with substantial spacing between them depending on the size and geometry of the objects to be manipulated. For convenience, description of the device of this invention may hereafter be expressed in terms of tubes, it being understood that the term xe2x80x9ctubesxe2x80x9d is not limited to separable cylindrical conduits. The term xe2x80x9cpneumaticxe2x80x9d refers to the gaseous fluid flow patterns at the surface resulting from the blowing and sucking functions of the conduits or tubes.
A pneumatic active surface device, PASD, which can be programmed to locate and control motion of an object, is provided by this invention. The appropriate choice of force, caused by blowing or sucking air flow through tubes of the pneumatic active surface device, is shown to cause objects placed on the array of tubes to be moved in useful ways. The device of this invention, as disclosed herein, offers great flexibility and speed and it can be employed to position, orient, identify, sort, feed, and assemble parts or objects. In addition multiple objects can be controlled simultaneously.
A preferred device of this invention provides a new process or method of handling objects that can be embodied in a variety of different devices or products. The invention is used to accurately locate, hold, position and move objects. Briefly, in accordance with a preferred embodiment of the present invention the device includes an active pneumatic surface that comprises a bundle of parallel tubes arranged so that the wallends of the tubes or the body surface between the conduits form a smooth surface, herein called the active pneumatic surface. This is the surface on which an object is observed and handled. The tubes are adapted by available support devices to selectively conduct air to and from the surface through the bore of each individual tube. The airflow through the bore of each tube is controlled individually through the use of suitable variable position valves such as 2- or 3-position valves or proportional valves. In one position pressurized air is supplied to the tube, in the other position a vacuum is drawn generating a sucking action. Three way valves provide a position which the gas flow is neither positive or negative but corresponds to ambient conditions. The pressurized air is used to push an object away while the vacuum is used to pull an object or draw it to the surface. As the object moves valves are opened and closed as needed. Air streams below, above, and around the object co-act to modify the position of the object and the path it will follow as it is moved around on the active surface. The air streams can be used to achieve translational, rotational, and flipping motion. The term xe2x80x9cflippingxe2x80x9d refers to juxtaposition of the opposite surfaces of the object as hereinafter described.
A sensor such as a force sensor, a pressure or gaseous fluid flow sensor is attached to each tube between the active surface and the valve. If a vacuum is drawn and an object covers the end of a tube, then the pressure in that tube will drop more than if the tube is not covered. By reading the pressure or gas flow rate in each tube while a vacuum is drawn the location of an object on the surface is identified. A computer can be used to process and display the sensor output and also to control the position of the individual valves suitable sensors include pressure, flow rate, and force sensors.